Stress has been, and still is, a difficult thing to measure. One difficulty in measuring stress comes directly from the lack of a concise definition for stress. One definition of stress is: “Stress is the non specific response of the body to any demand.” (Hans Selye, “Stress without Distress,” published by Philadelphia: Lippincott, 1974.) Another difficulty in measuring stress is in its diagnoses. Stress reveals itself by a constellation of common symptoms with varying degrees of specificity. Stress is difficult to diagnose because it reveals itself by a constellation of common symptoms with varying degrees of specificity. The patterns are a function of: the stimulus (demand or pressure), their build up, as well as the individual organism predisposition (weak links).
Examples of common “weak links” and the symptoms of their malfunction are as follows: (1) brain overstress: fatigue, aches and pains, crying spells, depression, anxiety attacks, insomnia, brain shrinkage; (2) gastrointestinal tract: ulcer, cramps and diarrhea, colitis, IBS, thyroid gland malfunction; (3) others: itchy skin rashes, decrease resistance to infections, high blood pressure, heart attack, stroke, etc.
Another difficulty is the complexity of the human stress response. To measure stress, “mind and body” both have to be taken into consideration, as there is no psychological event without a resulting somatic (bodily) event and vice versa. Stress has both psychological and physiological components; measuring only one component is insufficient to provide a complete understanding. Stress response varies greatly between individuals. One person, for instance, may display large changes in electrodermal activity with increased stress and show only moderate changes in heart rate and peripheral blood flow volume, while another individual may show the reverse pattern.
FIG. 1, based on work by Dr. George Everly (as modified by one of the present inventors), shows a model of the human stress response that provides a framework for understanding the places in the stress response that are amenable to measures. The stress response begins with a stressor event setting into motion a cascade of biological processes which gets interpreted by the brain. This interpretation is influenced by a variety of physical, psychological, and social factors. Once the event occurs the cognitive/affective domain is the critical “causal” phase in most stress responses. Cognitive appraisal is how a person perceives the stress which, like beauty, appears to in the eye of the beholder. Affective integration is the effect of the emotional well-being. Both are influenced by biological predispositions, personality patterns, learning history, and resources.
If the event is perceived as a threat, the body begins the stress response which proceeds through three stages:
(1) Neural: There is an immediate activation of the sympathetic nervous system, which results in reduced peripheral blood flow, accelerated heartbeats, dilated pupils, thickened saliva, and several other physiological changes.
(2) Neuroendocrine: There is a near immediate effect of releasing hormones, such as epinephrine (adrenaline) and norepinephrine (noradrenaline), that will activate the endocrine system and kick in the “fight or flight” response.
(3) Endocrine: The endocrine glands release a flood of powerful stress hormones such as ACTH and cortisol that cause a prolonged stress reaction.
All of the above results in some form of coping behavior. Certain forms of “treatment” for stress have been practiced or theorized in the past. Psychotherapy has been used for more adaptive health promoting cognitive/affective style. Another manner of treatment has used certain types of products, such as: techniques, games, or conditioning the mind and reducing stress-arousing thoughts such as “mind chatter”, bad memories or anticipations. Other forms of therapy have included: music or aromatherapy (reported to trigger memory and mood change), which are known to direct thoughts so as to produce peace and tranquility.
Aromatherapy has existed as folklore for centuries, but there has been very little rigorous scientific investigation of aromatheraputic effects on human psychology and physiology. There are many scientific, social, and economic reasons for this. Some of the scientific difficulties in measuring aromatheraputic effects are as follows:
(1) Aromatheraputic claims tend to be broad and ill-defined, using somewhat ambiguous words like soothing, harmonizing, happiness, sensuality, well being, etc. (2) Stress is also somewhat ambiguous and ill-defined. There is no standard definition of stress and, consequently, there are no widely accepted standards for measuring stress. One reason for this is that every person's psychological and physiological response to stress is different and can change over time. (3) The magnitude of aromatheraputic effects is probably small, making them difficult to isolate. (4) The mind-body connection is particularly strong here. There is much scientific evidence that a person's physiological reaction to an odorant may depend on their psychological response to the odorant, i.e., whether or not the person likes the odor. (5) Animal studies by Buchbauer indicate that only specific varieties of essential oils—indeed, in some cases only specific enantiomers of fragrance molecules—produce an aromatheraputic effect. This could explain some of the contradictory findings in the scientific literature regarding aromatherapy. A generic lavender, for instance, might not contain the correct amounts, proportions, or chemical species of the various components which are needed to produce an effect.
Some patent literature in the prior art has dealt with stress measurements: a method for measuring “Antistress Effects of Fragrances” was disclosed in KOKAI Patent Application No. HE11 (1991) 19076, by Pola Chemical Industry, Inc. A psychological stress was applied in the presence of a fragrance, and a saliva sample was collected before and after the exposure. The concentration of the adrenocorticol hormones in the saliva was determined. Unfortunately, this methodology is rather invasive (as would be blood or urine samples), and is not desirable as it increases the test subject's stress and adds complexity to the measurements. The adrenocorticol hormones are released in a secondary step, and have a short life in acute stress, and further may not get released in sufficient amounts to be measured. They are very difficult to measure in acute stress due to their short half-life.
In another patent document, by Warren et. al EP 0183436 B2 (1991) stress was measured by systolic blood pressure and a self administered questionnaire, in which respondents indicated their degree of relaxation, anger, anxiety, happiness, tenseness, embarrassment, calmness, fear, and sleepiness on a 7-point scale. A number of active odorants was found to significantly have an effect on the above human parameters when administered either alone or incorporated into a complex fragrance. These findings paralleled the measurements on systolic blood pressure taken in the same experiment. However, one measurement is not determinative, and no one has found a relation between most of the above basic emotions and blood pressure.
One of the failings of the majority of previous “stress-measuring” methodologies is that only one type of stress component was being evaluated: either physiological attributes or psychological attributes, but not both. One exception to this was disclosed in a paper published by the Oxford University Press in 2001, titled, “Effects of Chiral Fragrances on Human Autonomic Nervous System Parameters and Self-evaluation,” by Eva Heuberger, et al. However, even this paper did not provide a methodology for measuring the effects of fragrances in both “stress” and “relaxation” cycles.
Another paper titled, “Basic emotions induced by odorants: a new approach based on autonomic pattern results,” by Vernet-Maury, et al., appearing in the Journal of the Autonomic Nervous System, Volume 75, 1999, pages 176–183, is an example of prior art that uses multiple physiological measurements. However, Vernet-Maury, et al. do not use these measurements to measure stress; instead, the measurements are used in an attempt to classify a subject's response to an odorant to one of the basic emotions (i.e., happiness, surprise, sadness, fear, disgust, or anger). This paper does not provide a methodology for evaluating stress, and also does not use odorants in “stress” and “relaxation” cycles.
Yet another paper titled, “Aromatherapy Positively Affects Mood, EEG Patterns of Alertness and Math Computations,” by Diego, et al., appearing in the International Journal of Neuroscience, Volume 96, 1998, pages 217–224, describes an experiment using EEG sensors to monitor the brainwaves of subjects before, during, and after aromatherapy is administered. In this paper, quick answer questionnaires are administered to ascertain the effect of odorants on mood and anxiety of subjects. The methodology described in this paper does not evaluate the effects of odorants during stress, and does not utilize “stress” and “relaxation” cycles.